Different LEDs are driven by different activating voltages. The activating voltage for driving the LED is dependent on the color of the LEDs, such as the activating voltage for red LED is 2.1 voltage, and the activating voltage for white or blue LED is 3.2 voltage. In other words, it is impossible to use one single battery of 1.5 voltage to drive all LEDs. Therefore, if there is a circuit apparatus being able to drive various LEDs with low voltage, the problem of the different activating voltages for the various LEDs will be solved.
Many low-voltage driving circuit apparatuses containing more than one transistor or integrated circuit component have been developed. The prior art has disclosed one low-voltage circuit apparatus applied on driving LED, and the circuit apparatus contains just two transistors, an inductor and a capacitor (as shown in FIG. 1). The low-voltage circuit apparatus disclosed in this prior art contains the least components and provides the effective circuit apparatus without using the transformer.
Due to the positive pulse voltage driven by the capacitor on the low-voltage circuit apparatus of the prior art, there are some limitations on the brightness of the LED. If the circuit apparatus doesn't change the component numbers, it could not achieve the purpose of driving the LED brighter. In order to achieve the purpose of driving the LED brighter, the present invention changes the direction of the polarity on the circuit components (FIG. 2) and develops a new circuit apparatus (FIG. 3) according to the prior art.